﻿using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace Fcdbas.Core.Security
{
    /// <summary>数据助手</summary>
    public static class DataHelper
    {
        #region 散列
        /// <summary>MD5散列</summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static String Hash(String str)
        {
            //if (String.IsNullOrEmpty(str)) throw new ArgumentNullException("str");
            if (String.IsNullOrEmpty(str)) return null;

            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
            Byte[] by = md5.ComputeHash(Encoding.UTF8.GetBytes(str));
            return BitConverter.ToString(by).Replace("-", "");
        }

        /// <summary>文件散列</summary>
        /// <param name="filename"></param>
        /// <returns></returns>
        public static String HashFile(String filename)
        {
            if (String.IsNullOrEmpty(filename)) throw new ArgumentNullException("filename");

            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
            //Byte[] buffer = md5.ComputeHash(File.ReadAllBytes(filename));
            using (FileStream stream = new FileStream(filename, FileMode.Open, FileAccess.Read))
            {
                Byte[] buffer = md5.ComputeHash(stream);
                return BitConverter.ToString(buffer).Replace("-", "");
            }
        }
        #endregion

        #region CRC校验
        #region CRC16
        /// <summary>CRC校验</summary>
        /// <param name="stream"></param>
        /// <returns></returns>
        public static Int16 CRC16(Stream stream)
        {
            UInt16 crc = 0;

            while (stream.Position <= stream.Length)
            {
                UInt16 high = (UInt16)(crc / 256); //取CRC高8位
                crc <<= 8;
                Int32 b = stream.ReadByte();
                if (b == -1) break;
                crc ^= crc_ta_8[high ^ (Byte)b];
            }

            return (Int16)crc;
        }

        /// <summary>CRC校验</summary>
        /// <param name="buffer"></param>
        /// <returns></returns>
        public static Int16 CRC16(Byte[] buffer)
        {
            UInt16 crc = 0;
            for (Int32 i = 0; i < buffer.Length; i++)
            {
                UInt16 high = (UInt16)(crc / 256); //取CRC高8位
                crc <<= 8;
                crc ^= crc_ta_8[high ^ buffer[i]];
            }

            return (Int16)crc;
        }

        /// <summary>CRC校验文件</summary>
        /// <param name="filename"></param>
        /// <returns></returns>
        public static Int16 CRC16(String filename)
        {
            if (String.IsNullOrEmpty(filename)) throw new ArgumentNullException("filename");

            using (FileStream stream = new FileStream(filename, FileMode.Open, FileAccess.Read))
            {
                return CRC16(stream);
            }
        }

        #region 表
        static ushort[] crc_ta_8 = new ushort[] { /* CRC 字节余式表 */
    0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
    0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
    0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
    0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
    0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
    0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
    0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
    0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
    0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
    0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
    0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
    0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
    0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
    0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
    0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
    0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
    0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
    0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
    0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
    0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
    0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
    0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
    0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
    0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
    0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
    0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
    0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
    0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
    0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
    0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
    0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
    0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
};
        #endregion
        #endregion

        #region CRC32
        #region 表
        readonly static uint[] Crc32Table = new uint[] { 
               0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419,
			0x706AF48F, 0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4,
			0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07,
			0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
			0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856,
			0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9,
			0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4,
			0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
			0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3,
			0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC, 0x51DE003A,
			0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599,
			0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
			0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190,
			0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F,
			0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E,
			0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
			0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED,
			0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950,
			0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3,
			0xFBD44C65, 0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
			0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A,
			0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5,
			0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA, 0xBE0B1010,
			0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
			0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17,
			0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6,
			0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615,
			0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
			0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 0xF00F9344,
			0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB,
			0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A,
			0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
			0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1,
			0xA6BC5767, 0x3FB506DD, 0x48B2364B, 0xD80D2BDA, 0xAF0A1B4C,
			0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF,
			0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
			0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE,
			0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31,
			0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C,
			0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
			0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B,
			0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
			0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1,
			0x18B74777, 0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
			0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45, 0xA00AE278,
			0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7,
			0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66,
			0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
			0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605,
			0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8,
			0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B,
			0x2D02EF8D
              };
        #endregion

        /// <summary>CRC校验</summary>
        /// <param name="stream"></param>
        /// <returns></returns>
        public static Int16 CRC32(Stream stream)
        {
            UInt32 crc = 0;
            crc ^= 0xFFFFFFFF;
            while (stream.Position <= stream.Length)
            {
                Int32 b = stream.ReadByte();
                if (b == -1) break;
                crc = ((crc >> 8) & 0x00FFFFFF) ^ Crc32Table[(crc ^ (Byte)b) & 0xFF];
            }

            return (Int16)(crc ^ 0xFFFFFFFF);
        }

        /// <summary>CRC校验</summary>
        /// <param name="buffer"></param>
        /// <returns></returns>
        public static Int16 CRC32(Byte[] buffer)
        {
            UInt32 crc = 0;
            crc ^= 0xFFFFFFFF;
            for (Int32 i = 0; i < buffer.Length; i++)
            {
                crc = ((crc >> 8) & 0x00FFFFFF) ^ Crc32Table[(crc ^ buffer[i]) & 0xFF];
            }
            return (Int16)(crc ^ 0xFFFFFFFF);

            //Crc32 crc = new Crc32();
            //crc.Update(buffer);
            //return (UInt32)crc.Value;
        }

        /// <summary>CRC校验文件</summary>
        /// <param name="filename"></param>
        /// <returns></returns>
        public static Int16 CRC32(String filename)
        {
            if (String.IsNullOrEmpty(filename)) throw new ArgumentNullException("filename");

            using (FileStream stream = new FileStream(filename, FileMode.Open, FileAccess.Read))
            {
                return CRC32(stream);
            }
        }
        #endregion
        #endregion

        #region 加解密
        private static SymmetricAlgorithm GetProvider(String key)
        {
            SymmetricAlgorithm sa = new TripleDESCryptoServiceProvider();
            Int32 max = sa.LegalKeySizes[0].MaxSize / 8;
            //key = Hash(key);
            String str = key;
            Byte[] bts = Convert.FromBase64String(str);//Encoding.UTF8.GetBytes(str);

            if (bts.Length != max) Array.Resize<Byte>(ref bts, max);

            sa.Key = bts;

            //max = sa.LegalBlockSizes[0].MaxSize / 8;
            //bts = Encoding.UTF8.GetBytes(str);
            ////倒序
            //Array.Reverse(bts);
            //if (bts.Length != max) Array.Resize<Byte>(ref bts, max);
            sa.IV = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 }; //bts;

            return sa;
        }
        private static String byte2hex(byte[] b)
        {
            StringBuilder hs = new StringBuilder();
            String stmp;
            for (int n = 0; b != null && n < b.Length; n++)
            {
                stmp = (b[n] & 0XFF).ToString("x");
                if (stmp.Length == 1)
                    hs.Append('0');
                hs.Append(stmp);
            }
            return hs.ToString().ToUpper();
        }

        private static byte[] hex2byte(byte[] b)
        {
            if ((b.Length % 2) != 0)
                throw new Exception();
            byte[] b2 = new byte[b.Length / 2];
            for (int n = 0; n < b.Length; n += 2)
            {
                byte[] b3 = new byte[2];
                b3[0] = b[n];
                b3[1] = b[n + 1];
                String item = System.Text.Encoding.Default.GetString(b3);
                b2[n / 2] = (byte)Int32.Parse(item, System.Globalization.NumberStyles.HexNumber);
            }
            return b2;
        }
        /// <summary>TripleDES加密</summary>
        /// <param name="content">UTD8编码的明文</param>
        /// <param name="key">密码字符串经MD5散列后作为DES密码</param>
        /// <returns></returns>
        public static String Encrypt(String content, String key)
        {
            if (String.IsNullOrEmpty(content)) throw new ArgumentNullException("content");
            Byte[] data = Encoding.UTF8.GetBytes(content);

            data = Encrypt(data, key);
            return byte2hex(data);
            //return Convert.ToBase64String(data);
        }

        /// <summary>TripleDES加密</summary>
        /// <param name="data"></param>
        /// <param name="key">密码字符串经MD5散列后作为DES密码</param>
        /// <returns></returns>
        public static Byte[] Encrypt(Byte[] data, String key)
        {
            if (data == null || data.Length < 1) throw new ArgumentNullException("data");
            if (String.IsNullOrEmpty(key)) throw new ArgumentNullException("key");

            MemoryStream outstream = new MemoryStream();
            CryptoStream stream = new CryptoStream(outstream, GetProvider(key).CreateEncryptor(), CryptoStreamMode.Write);
            stream.Write(data, 0, data.Length);
            stream.FlushFinalBlock();

            data = outstream.ToArray();

            stream.Close();
            outstream.Close();

            return data;
        }

        /// <summary>TripleDES解密</summary>
        /// <param name="content">UTD8编码的密文</param>
        /// <param name="key">密码字符串经MD5散列后作为DES密码</param>
        /// <returns></returns>
        public static String Descrypt(String content, String key)
        {
            if (String.IsNullOrEmpty(content)) throw new ArgumentNullException("content");
            Byte[] data = System.Text.Encoding.UTF8.GetBytes(content);
            byte[] data1 = hex2byte(data);
            data = Descrypt(data1, key);

            return Encoding.UTF8.GetString(data);
        }

        /// <summary>TripleDES解密</summary>
        /// <param name="data"></param>
        /// <param name="key">密码字符串经MD5散列后作为DES密码</param>
        /// <returns></returns>
        public static Byte[] Descrypt(Byte[] data, String key)
        {
            if (data == null || data.Length < 1) throw new ArgumentNullException("data");
            if (String.IsNullOrEmpty(key)) throw new ArgumentNullException("key");

            MemoryStream ms = new MemoryStream(data);
            CryptoStream stream = new CryptoStream(ms, GetProvider(key).CreateDecryptor(), CryptoStreamMode.Read);

            MemoryStream ms2 = new MemoryStream();
            while (true)
            {
                Byte[] buffer = new Byte[10];
                Int32 count = stream.Read(buffer, 0, buffer.Length);
                if (count <= 0) break;

                ms2.Write(buffer, 0, count);
                if (count < buffer.Length) break;
            }

            data = ms2.ToArray();

            stream.Close();
            ms.Close();
            ms2.Close();

            return data;
        }
        #endregion

        #region RC4加密
        /// <summary>RC4加密解密</summary>
        /// <param name="data">数据</param>
        /// <param name="pass">UTF8编码的密码</param>
        /// <returns></returns>
        public static Byte[] RC4(Byte[] data, String pass)
        {
            if (data == null || pass == null) return null;
            Byte[] output = new Byte[data.Length];
            Int64 i = 0;
            Int64 j = 0;
            Byte[] mBox = GetKey(Encoding.UTF8.GetBytes(pass), 256);

            // 加密
            for (Int64 offset = 0; offset < data.Length; offset++)
            {
                i = (i + 1) % mBox.Length;
                j = (j + mBox[i]) % mBox.Length;
                Byte temp = mBox[i];
                mBox[i] = mBox[j];
                mBox[j] = temp;
                Byte a = data[offset];
                //Byte b = mBox[(mBox[i] + mBox[j] % mBox.Length) % mBox.Length];
                // mBox[j] 一定比 mBox.Length 小，不需要在取模
                Byte b = mBox[(mBox[i] + mBox[j]) % mBox.Length];
                output[offset] = (Byte)((Int32)a ^ (Int32)b);
            }

            return output;
        }

        /// <summary>打乱密码</summary>
        /// <param name="pass">密码</param>
        /// <param name="kLen">密码箱长度</param>
        /// <returns>打乱后的密码</returns>
        static Byte[] GetKey(Byte[] pass, Int32 kLen)
        {
            Byte[] mBox = new Byte[kLen];

            for (Int64 i = 0; i < kLen; i++)
            {
                mBox[i] = (Byte)i;
            }
            Int64 j = 0;
            for (Int64 i = 0; i < kLen; i++)
            {
                j = (j + mBox[i] + pass[i % pass.Length]) % kLen;
                Byte temp = mBox[i];
                mBox[i] = mBox[j];
                mBox[j] = temp;
            }
            return mBox;
        }
        #endregion

        #region RSA签名
        /// <summary>签名</summary>
        /// <param name="data"></param>
        /// <param name="priKey"></param>
        /// <returns>Base64编码的签名</returns>
        internal static String Sign(Byte[] data, String priKey)
        {
            if (data == null | String.IsNullOrEmpty(priKey)) return null;

            var rsa = new RSACryptoServiceProvider();
            var md5 = new MD5CryptoServiceProvider();
            try
            {
                rsa.FromXmlString(priKey);
                return Convert.ToBase64String(rsa.SignHash(md5.ComputeHash(data), "1.2.840.113549.2.5"));
            }
            catch { return null; }
        }
        #endregion

        #region RSA验证签名
        /// <summary>验证签名</summary>
        /// <param name="data">待验证的数据</param>
        /// <param name="signdata">Base64编码的签名</param>
        /// <param name="pubKey">公钥</param>
        /// <returns></returns>
        internal static Boolean Verify(Byte[] data, String signdata, String pubKey)
        {
            if (data == null ||
                data.Length < 1 ||
                String.IsNullOrEmpty(signdata) ||
                String.IsNullOrEmpty(pubKey)) return false;

            var rsa = new RSACryptoServiceProvider();
            var md5 = new MD5CryptoServiceProvider();
            try
            {
                rsa.FromXmlString(pubKey);
                return rsa.VerifyHash(md5.ComputeHash(data), "1.2.840.113549.2.5", Convert.FromBase64String(signdata));
            }
            catch { return false; }
        }
        #endregion

        #region 编码
        /// <summary>把字节数组编码为十六进制字符串</summary>
        /// <param name="data"></param>
        /// <param name="offset"></param>
        /// <param name="count"></param>
        /// <returns></returns>
        public static String ToHex(this Byte[] data, Int32 offset = 0, Int32 count = 0)
        {
            if (data == null || data.Length < 1) return null;
            if (count <= 0) count = data.Length - offset;

            //return BitConverter.ToString(data).Replace("-", null);
            // 上面的方法要替换-，效率太低
            Char[] cs = new Char[count * 2];
            // 两个索引一起用，避免乘除带来的性能损耗
            for (int i = 0, j = 0; i < count; i++, j += 2)
            {
                Byte b = data[offset + i];
                cs[j] = GetHexValue(b / 0x10);
                cs[j + 1] = GetHexValue(b % 0x10);
            }
            return new String(cs);
        }

        private static char GetHexValue(int i)
        {
            if (i < 10) return (char)(i + 0x30);
            return (char)(i - 10 + 0x41);
        }

        /// <summary>解密</summary>
        /// <param name="data"></param>
        /// <returns></returns>
        public static Byte[] FromHex(String data)
        {
            if (String.IsNullOrEmpty(data)) return null;

            Byte[] bts = new Byte[data.Length / 2];
            for (int i = 0; i < data.Length / 2; i++)
            {
                bts[i] = (Byte)Convert.ToInt32(data.Substring(2 * i, 2), 16);
            }
            return bts;
        }
        #endregion
    }
}